Concrete Vs. Asphalt
Concrete and asphalt are both good options for a paving project, but only one is a solid long-term investment that will last for decades and give you a multitude of design options.
When you’re starting a paving project, you have some choices when it comes to the materials you use. Concrete and asphalt are both valid choices for a driveway, parking lot, patio, or even a highway, and at first glance they might not seem that different. But if you take a closer look at the durability, maintenance, quantity required for each material, and decorative options, the differences will start to reveal themselves.
To help you make an informed decision before starting your next paving project, here is a breakdown of each material.
The decision of whether to use concrete or asphalt for your paving project will depend on several factors. The type of project, durability, and your project timeline should all be considered when choosing the right material. Let’s explore some of those factors.
The longest parts of your paving project will be the material laying and curing processes.
Because concrete requires up to seven days to completely cure before traffic can be allowed on it, businesses often choose asphalt for parking lot projects to avoid business disruptions. Asphalt has a timeline of 48 to 72 hours before it is dry enough for foot and vehicle traffic. Resurfaced asphalt can be ready in a few hours. The curing time of concrete depends on the weather, and this should be taken into consideration. In the summer, light traffic like cars, SUVs, and pickup trucks can usually drive on the new concrete pavement in about two days.
If you consider the build time and not just the curing time, your timeline changes. Most asphalt driveways or parking lots require at least two applications of layers 1.5 to 2 inches thick to support vehicle traffic for a longer period. The first application of asphalt will not be strong enough to sustain traffic for any extended length of time. Concrete, on the other hand, is spread in one full layer of 4 to 8 inches. This means concrete projects have half the construction time as asphalt overall, resulting in less disruption.
When you are considering the timeline of your project, you should factor in:
To get an accurate timeline for the entire process you should talk to your contractor.
When you’re ready to start your next paving project, whether it’s a commercial parking lot, a residential driveway or a decorative patio for a business or residence, you’re going to have to have to decide which material is best. After looking at which material costs more upfront and which is the better long-term investment, you’ll want to consider the project itself and ask a few questions:
Among all these questions, the function of your project will be one of the most important things to consider as it will determine the strength and thickness of the material you choose.
Here is a breakdown of the suggested thickness of concrete and asphalt based on the type of traffic it will see.
Light use: 4” —Light use includes residential driveways or parking for passenger cars, trucks, and occasional use by heavier trucks.
Medium use: 5”—Medium use includes driveways and parking areas for light to medium trucks and some heavy trucks.
Heavy use: 6”—Heavy use includes driveways and parking areas for heavy, commercial and industrial trucks.
Light use: 6-8" granular base aggregate with 2-3" asphalt—Light use includes residential driveways or parking for passenger cars, trucks, and occasional use by heavier trucks.
Medium use: 8" granular base aggregate with 4" asphalt—Medium use includes driveways and parking areas for light to medium trucks and some heavy trucks.
Heavy use: 6” hot mix asphalt layer on top of an 8” aggregate base layer—Heavy use includes driveways and parking areas for heavy, commercial and industrial trucks.
For asphalt, the exact thickness depends on the type of subgrade soil and the thickness and type of aggregate base placed between the subgrade and asphalt.
The strength of concrete must not be ignored. Compared to asphalt, a 5” concrete pavement has the same load carrying capacity as an 8” asphalt pavement. So, for parking lots or garages where large capacity trucks will be parking and driving, concrete is the stronger choice.
If your project requires design versatility, concrete is the best material for your project. The makeup of concrete gives it strength and also allows it to be shaped and molded into shapes and designs that add a pleasing aesthetic to any project.
If you’re paving a residential driveway, patio, or entryway, you don’t need to stick with flat and gray as your design aesthetic. Here are just a few of the options concrete has to offer. You can get:
Concrete is a great choice for any project where you’ll want flexibility in design.
Asphalt gets soft when consistently exposed to hot temperatures, putting it at risk for cracks and holes. It also absorbs heat, making it difficult to walk or play on during hotter months. This ability to absorb heat will even raise the temperature in cars parked on asphalt during a hot day. Concrete can stay as many as 10 degrees cooler than asphalt which makes it a better choice in climates with higher temperatures.
By considering the scope of your project, your timeline and the weather, you’ll be able to choose the material that will work best for your particular situation
Before you get started on your paving project, be aware that it’s not just about the material you choose.
No matter the material you choose for your parking lot, driveway, road, or patio project, making the proper considerations before pouring the concrete can drastically impact the lifespan of the product.
Before concrete is poured, here are some factors that will impact how long the concrete lasts, how much maintenance it will require, and the overall quality of the product.
The subgrade is the natural ground on which the concrete area is constructed.
A good subgrade:
Your subbase, usually a layer of sand or gravel that is placed on top of the prepared subgrade, will depend on the material you choose for the project.
An asphalt parking lot usually needs a bed of gravel 6 to 8 inches deep installed under the asphalt. This can be a complicated process; if the asphalt is poured before the gravel settles, the asphalt will crack and split as the stones beneath it shift.
For a concrete parking lot, no special subbase material is required if you’ve properly prepared the subgrade. Only light layer of sand or gravel is necessary.
No matter the material you choose, an uneven, poorly drained base will affect the surface and lead to more potholes and excessive cracks. Use a project checklist to make sure you’ve properly prepared your base before you begin to pour your asphalt or concrete.
Here are a few items that should be included on a checklist:
It doesn’t matter which type of material you choose for a project if the proper steps aren’t taken to ensure the stability of the paved surface.
When it comes to choosing the right material for your next paving project, choosing the long-term investment over the cheapest investment is going to benefit you the most in the long run.
The upfront cost of concrete has traditionally been higher than asphalt. Over the last few years, however, the rising price of oil has caused the price of asphalt to rise. As the price of asphalt fluctuates, it’s the long-term costs that make concrete the better purchase. To understand why concrete might cost more, let’s break down the costs using a 600-square-foot driveway.
*All cost estimates provided by Home Advisor. Prices may vary widely based on a number of other factors.
The price of the individual materials might give you pause but look at the cost per year.
This difference in yearly costs has to do with the maintenance required for concrete and asphalt, which we will look at in the next section.
But why is concrete generally more expensive than asphalt? The answer comes from the ingredients that make up concrete.
Concrete is made of:
Aggregates: This is what binds the concrete’s paste together. Aggregates can be sand, gravel, or crushed stone.
Paste: Concrete paste is a combination of water and portland cement.
Portland Cement: Portland cement is created by grinding limestone or chalk, alumina, and silica which are found in shale and clay. These materials are then blended and burned in large kilns until they begin to fuse into small masses called clinker. After the clinker cools down, gypsum is added, and the hardened materials are ground down again, resulting in a fine powder.
These ingredients make concrete highly versatile, malleable, and easy-to-form yet strong and durable. This combination of characteristics makes concrete extremely sought after, therefore raising the price.
Factors that can impact the price of concrete include:
Don't let the upfront cost turn you away from concrete. When choosing the material for your next project, choose the one that will deliver ongoing savings over the years.
Looking at the cost of concrete and asphalt tells you what you will pay up front to pave a driveway or road, but city planners and homeowners should also know what they will need to invest over the years to take care of their concrete road, patio, or parking lot. Let's take a look at the long-term savings by project.
The Michigan Department of Transportation (MDOT) reports that the average life expectancy of concrete pavement is 27.5 years before repairs are needed. The average life expectancy of an asphalt roadway is much less at only 15.5 years, according to MDOT. Federally funded studies show concrete interstate highways across the United States last about 2.5 times longer on average than asphalt highways.
The secret behind the strength of concrete is the careful proportioning and mixing of its ingredients. A good mix of large and fine aggregates binds tightly and is more impervious to rain, ice and other external forces. This is particularly important in states like Michigan and Minnesota that experience extreme temperature swings that can crack roadways. Many exterior concrete mixtures have a 5 to 8% air content which gives it the ability to withstand frequent freezes and thaws. Minnesota recognizes the durability of concrete and has a new concrete pavement design that is expected to last more than 60 years with very little maintenance.
On a smaller scale, according to Home Advisor, a concrete 600-square-foot driveway will cost $93.86 per year over its expected 35-year lifetime. The same asphalt drive would cost $125 for each year of its 20-year lifetime.
Over the years, the elements will cause asphalt to change color and its structure to weaken. To avoid cracks and holes that could endanger the public or the employees that drive on it, asphalt should be completely recoated every 5 to 10 years.
Concrete, on the other hand, only needs to be cleaned every so often and, depending on the weather where you live, might need to be sealed in sections every five or so years. Cleaning and sealing are much more affordable options than completely resurfacing every few years, so take care of your concrete to ensure it’s a smart, long-term investment.
With proper materials, construction, curing, and long-term care, your new concrete pavement could last close to a lifetime.
If you’ve considered longevity, durability, and versatility and have decided to choose concrete for your next paving project, you want to make sure you work with a concrete contractor who is going to get the job done right.
At the Michigan Concrete Association, it’s our mission to increase the use of concrete and give support to Michigan’s paving industry.
Our association includes 200 companies that offer concrete paving services across the state.
Selecting the right concrete contractor for the size and scope of your job is going to make your projects run much more smoothly, and just like you’ll need to choose the best material for your project, you’ll need to choose the best type of concrete contractor for your project. The basic categories of concrete suppliers are:
No matter the type of project, you need someone who is certified to do the type of work you need. In the concrete world, that certification is the American Concrete (ACI) Institute Flatwork Finisher certification.
An ACI certified contractor will:
At the Michigan Concrete Association, we are proud to work with contractors across Michigan that meet this description. No matter where you are located, you can find a certified concrete contractor to complete your concrete project. From airports and highways to residential and city sidewalks, when you browse our list of concrete contractors, you’ll find a contractor you can work with.
When you're looking at paving materials, it's important to look past the initial cost and look to the factors that will come into play before, during, and after installation. For a flexible material that will last a long time with very little maintenance, consider concrete.